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  <div class="section" id="module-xml.parsers.expat">
<h1>20.5. <tt class="xref docutils literal"><span class="pre">xml.parsers.expat</span></tt> &#8212; Fast XML parsing using Expat<a class="headerlink" href="#module-xml.parsers.expat" title="Permalink to this headline">¶</a></h1>
<p>
<span class="versionmodified">New in version 2.0.</span></p>
<p id="index-495">The <tt class="xref docutils literal"><span class="pre">xml.parsers.expat</span></tt> module is a Python interface to the Expat
non-validating XML parser. The module provides a single extension type,
<tt class="xref docutils literal"><span class="pre">xmlparser</span></tt>, that represents the current state of an XML parser.  After
an <tt class="xref docutils literal"><span class="pre">xmlparser</span></tt> object has been created, various attributes of the object
can be set to handler functions.  When an XML document is then fed to the
parser, the handler functions are called for the character data and markup in
the XML document.</p>
<p id="index-496">This module uses the <tt class="xref docutils literal"><span class="pre">pyexpat</span></tt> module to provide access to the Expat
parser.  Direct use of the <tt class="xref docutils literal"><span class="pre">pyexpat</span></tt> module is deprecated.</p>
<p>This module provides one exception and one type object:</p>
<dl class="exception">
<dt id="xml.parsers.expat.ExpatError">
<em class="property">
exception </em><tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">ExpatError</tt><a class="headerlink" href="#xml.parsers.expat.ExpatError" title="Permalink to this definition">¶</a></dt>
<dd>The exception raised when Expat reports an error.  See section
<a class="reference internal" href="#expaterror-objects"><em>ExpatError Exceptions</em></a> for more information on interpreting Expat errors.</dd></dl>

<dl class="exception">
<dt id="xml.parsers.expat.error">
<em class="property">
exception </em><tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">error</tt><a class="headerlink" href="#xml.parsers.expat.error" title="Permalink to this definition">¶</a></dt>
<dd>Alias for <a title="xml.parsers.expat.ExpatError" class="reference internal" href="#xml.parsers.expat.ExpatError"><tt class="xref docutils literal"><span class="pre">ExpatError</span></tt></a>.</dd></dl>

<dl class="data">
<dt id="xml.parsers.expat.XMLParserType">
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XMLParserType</tt><a class="headerlink" href="#xml.parsers.expat.XMLParserType" title="Permalink to this definition">¶</a></dt>
<dd>The type of the return values from the <a title="xml.parsers.expat.ParserCreate" class="reference internal" href="#xml.parsers.expat.ParserCreate"><tt class="xref docutils literal"><span class="pre">ParserCreate()</span></tt></a> function.</dd></dl>

<p>The <tt class="xref docutils literal"><span class="pre">xml.parsers.expat</span></tt> module contains two functions:</p>
<dl class="function">
<dt id="xml.parsers.expat.ErrorString">
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">ErrorString</tt><big>(</big><em>errno</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.ErrorString" title="Permalink to this definition">¶</a></dt>
<dd>Returns an explanatory string for a given error number <em>errno</em>.</dd></dl>

<dl class="function">
<dt id="xml.parsers.expat.ParserCreate">
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">ParserCreate</tt><big>(</big><span class="optional">[</span><em>encoding</em><span class="optional">[</span>, <em>namespace_separator</em><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#xml.parsers.expat.ParserCreate" title="Permalink to this definition">¶</a></dt>
<dd><p>Creates and returns a new <tt class="xref docutils literal"><span class="pre">xmlparser</span></tt> object.   <em>encoding</em>, if specified,
must be a string naming the encoding  used by the XML data.  Expat doesn&#8217;t
support as many encodings as Python does, and its repertoire of encodings can&#8217;t
be extended; it supports UTF-8, UTF-16, ISO-8859-1 (Latin1), and ASCII.  If
<em>encoding</em> <a class="footnote-reference" href="#id3" id="id1">[1]</a> is given it will override the implicit or explicit encoding of the
document.</p>
<p>Expat can optionally do XML namespace processing for you, enabled by providing a
value for <em>namespace_separator</em>.  The value must be a one-character string; a
<a title="exceptions.ValueError" class="reference external" href="exceptions.html#exceptions.ValueError"><tt class="xref docutils literal"><span class="pre">ValueError</span></tt></a> will be raised if the string has an illegal length (<tt class="xref docutils literal"><span class="pre">None</span></tt>
is considered the same as omission).  When namespace processing is enabled,
element type names and attribute names that belong to a namespace will be
expanded.  The element name passed to the element handlers
<tt class="xref docutils literal"><span class="pre">StartElementHandler</span></tt> and <tt class="xref docutils literal"><span class="pre">EndElementHandler</span></tt> will be the
concatenation of the namespace URI, the namespace separator character, and the
local part of the name.  If the namespace separator is a zero byte (<tt class="docutils literal"><span class="pre">chr(0)</span></tt>)
then the namespace URI and the local part will be concatenated without any
separator.</p>
<p>For example, if <em>namespace_separator</em> is set to a space character (<tt class="docutils literal"><span class="pre">'</span> <span class="pre">'</span></tt>) and
the following document is parsed:</p>
<div class="highlight-python"><pre>&lt;?xml version="1.0"?&gt;
&lt;root xmlns    = "http://default-namespace.org/"
      xmlns:py = "http://www.python.org/ns/"&gt;
  &lt;py:elem1 /&gt;
  &lt;elem2 xmlns="" /&gt;
&lt;/root&gt;</pre>
</div>
<p><tt class="xref docutils literal"><span class="pre">StartElementHandler</span></tt> will receive the following strings for each
element:</p>
<div class="highlight-python"><pre>http://default-namespace.org/ root
http://www.python.org/ns/ elem1
elem2</pre>
</div>
</dd></dl>

<div class="admonition-see-also admonition seealso">
<p class="first admonition-title">See also</p>
<dl class="last docutils">
<dt><a class="reference external" href="http://www.libexpat.org/">The Expat XML Parser</a></dt>
<dd>Home page of the Expat project.</dd>
</dl>
</div>
<div class="section" id="xmlparser-objects">
<span id="id2"></span><h2>20.5.1. XMLParser Objects<a class="headerlink" href="#xmlparser-objects" title="Permalink to this headline">¶</a></h2>
<p><tt class="xref docutils literal"><span class="pre">xmlparser</span></tt> objects have the following methods:</p>
<dl class="method">
<dt id="xml.parsers.expat.xmlparser.Parse">
<tt class="descclassname">xmlparser.</tt><tt class="descname">Parse</tt><big>(</big><em>data</em><span class="optional">[</span>, <em>isfinal</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.Parse" title="Permalink to this definition">¶</a></dt>
<dd>Parses the contents of the string <em>data</em>, calling the appropriate handler
functions to process the parsed data.  <em>isfinal</em> must be true on the final call
to this method.  <em>data</em> can be the empty string at any time.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.ParseFile">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ParseFile</tt><big>(</big><em>file</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.ParseFile" title="Permalink to this definition">¶</a></dt>
<dd>Parse XML data reading from the object <em>file</em>.  <em>file</em> only needs to provide
the <tt class="docutils literal"><span class="pre">read(nbytes)</span></tt> method, returning the empty string when there&#8217;s no more
data.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.SetBase">
<tt class="descclassname">xmlparser.</tt><tt class="descname">SetBase</tt><big>(</big><em>base</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.SetBase" title="Permalink to this definition">¶</a></dt>
<dd>Sets the base to be used for resolving relative URIs in system identifiers in
declarations.  Resolving relative identifiers is left to the application: this
value will be passed through as the <em>base</em> argument to the
<a title="xml.parsers.expat.xmlparser.ExternalEntityRefHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.ExternalEntityRefHandler"><tt class="xref docutils literal"><span class="pre">ExternalEntityRefHandler()</span></tt></a>, <a title="xml.parsers.expat.xmlparser.NotationDeclHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.NotationDeclHandler"><tt class="xref docutils literal"><span class="pre">NotationDeclHandler()</span></tt></a>, and
<a title="xml.parsers.expat.xmlparser.UnparsedEntityDeclHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.UnparsedEntityDeclHandler"><tt class="xref docutils literal"><span class="pre">UnparsedEntityDeclHandler()</span></tt></a> functions.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.GetBase">
<tt class="descclassname">xmlparser.</tt><tt class="descname">GetBase</tt><big>(</big><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.GetBase" title="Permalink to this definition">¶</a></dt>
<dd>Returns a string containing the base set by a previous call to <a title="xml.parsers.expat.xmlparser.SetBase" class="reference internal" href="#xml.parsers.expat.xmlparser.SetBase"><tt class="xref docutils literal"><span class="pre">SetBase()</span></tt></a>,
or <tt class="xref docutils literal"><span class="pre">None</span></tt> if  <a title="xml.parsers.expat.xmlparser.SetBase" class="reference internal" href="#xml.parsers.expat.xmlparser.SetBase"><tt class="xref docutils literal"><span class="pre">SetBase()</span></tt></a> hasn&#8217;t been called.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.GetInputContext">
<tt class="descclassname">xmlparser.</tt><tt class="descname">GetInputContext</tt><big>(</big><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.GetInputContext" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns the input data that generated the current event as a string. The data is
in the encoding of the entity which contains the text. When called while an
event handler is not active, the return value is <tt class="xref docutils literal"><span class="pre">None</span></tt>.</p>
<p>
<span class="versionmodified">New in version 2.1.</span></p>
</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.ExternalEntityParserCreate">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ExternalEntityParserCreate</tt><big>(</big><em>context</em><span class="optional">[</span>, <em>encoding</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.ExternalEntityParserCreate" title="Permalink to this definition">¶</a></dt>
<dd>Create a &#8220;child&#8221; parser which can be used to parse an external parsed entity
referred to by content parsed by the parent parser.  The <em>context</em> parameter
should be the string passed to the <a title="xml.parsers.expat.xmlparser.ExternalEntityRefHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.ExternalEntityRefHandler"><tt class="xref docutils literal"><span class="pre">ExternalEntityRefHandler()</span></tt></a> handler
function, described below. The child parser is created with the
<a title="xml.parsers.expat.xmlparser.ordered_attributes" class="reference internal" href="#xml.parsers.expat.xmlparser.ordered_attributes"><tt class="xref docutils literal"><span class="pre">ordered_attributes</span></tt></a>, <a title="xml.parsers.expat.xmlparser.returns_unicode" class="reference internal" href="#xml.parsers.expat.xmlparser.returns_unicode"><tt class="xref docutils literal"><span class="pre">returns_unicode</span></tt></a> and
<a title="xml.parsers.expat.xmlparser.specified_attributes" class="reference internal" href="#xml.parsers.expat.xmlparser.specified_attributes"><tt class="xref docutils literal"><span class="pre">specified_attributes</span></tt></a> set to the values of this parser.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.UseForeignDTD">
<tt class="descclassname">xmlparser.</tt><tt class="descname">UseForeignDTD</tt><big>(</big><span class="optional">[</span><em>flag</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.UseForeignDTD" title="Permalink to this definition">¶</a></dt>
<dd><p>Calling this with a true value for <em>flag</em> (the default) will cause Expat to call
the <a title="xml.parsers.expat.xmlparser.ExternalEntityRefHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.ExternalEntityRefHandler"><tt class="xref docutils literal"><span class="pre">ExternalEntityRefHandler</span></tt></a> with <a title="None" class="reference external" href="constants.html#None"><tt class="xref xref docutils literal"><span class="pre">None</span></tt></a> for all arguments to
allow an alternate DTD to be loaded.  If the document does not contain a
document type declaration, the <a title="xml.parsers.expat.xmlparser.ExternalEntityRefHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.ExternalEntityRefHandler"><tt class="xref docutils literal"><span class="pre">ExternalEntityRefHandler</span></tt></a> will still be
called, but the <a title="xml.parsers.expat.xmlparser.StartDoctypeDeclHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.StartDoctypeDeclHandler"><tt class="xref docutils literal"><span class="pre">StartDoctypeDeclHandler</span></tt></a> and
<a title="xml.parsers.expat.xmlparser.EndDoctypeDeclHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.EndDoctypeDeclHandler"><tt class="xref docutils literal"><span class="pre">EndDoctypeDeclHandler</span></tt></a> will not be called.</p>
<p>Passing a false value for <em>flag</em> will cancel a previous call that passed a true
value, but otherwise has no effect.</p>
<p>This method can only be called before the <a title="xml.parsers.expat.xmlparser.Parse" class="reference internal" href="#xml.parsers.expat.xmlparser.Parse"><tt class="xref docutils literal"><span class="pre">Parse()</span></tt></a> or <a title="xml.parsers.expat.xmlparser.ParseFile" class="reference internal" href="#xml.parsers.expat.xmlparser.ParseFile"><tt class="xref docutils literal"><span class="pre">ParseFile()</span></tt></a>
methods are called; calling it after either of those have been called causes
<a title="xml.parsers.expat.ExpatError" class="reference internal" href="#xml.parsers.expat.ExpatError"><tt class="xref docutils literal"><span class="pre">ExpatError</span></tt></a> to be raised with the <tt class="xref docutils literal"><span class="pre">code</span></tt> attribute set to
<tt class="xref docutils literal"><span class="pre">errors.XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING</span></tt>.</p>
<p>
<span class="versionmodified">New in version 2.3.</span></p>
</dd></dl>

<p><tt class="xref docutils literal"><span class="pre">xmlparser</span></tt> objects have the following attributes:</p>
<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.buffer_size">
<tt class="descclassname">xmlparser.</tt><tt class="descname">buffer_size</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.buffer_size" title="Permalink to this definition">¶</a></dt>
<dd><p>The size of the buffer used when <a title="xml.parsers.expat.xmlparser.buffer_text" class="reference internal" href="#xml.parsers.expat.xmlparser.buffer_text"><tt class="xref docutils literal"><span class="pre">buffer_text</span></tt></a> is true.
A new buffer size can be set by assigning a new integer value
to this attribute.
When the size is changed, the buffer will be flushed.</p>
<p>
<span class="versionmodified">New in version 2.3.</span></p>
<p>
<span class="versionmodified">Changed in version 2.6: </span>The buffer size can now be changed.</p>
</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.buffer_text">
<tt class="descclassname">xmlparser.</tt><tt class="descname">buffer_text</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.buffer_text" title="Permalink to this definition">¶</a></dt>
<dd><p>Setting this to true causes the <tt class="xref docutils literal"><span class="pre">xmlparser</span></tt> object to buffer textual
content returned by Expat to avoid multiple calls to the
<a title="xml.parsers.expat.xmlparser.CharacterDataHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.CharacterDataHandler"><tt class="xref docutils literal"><span class="pre">CharacterDataHandler()</span></tt></a> callback whenever possible.  This can improve
performance substantially since Expat normally breaks character data into chunks
at every line ending.  This attribute is false by default, and may be changed at
any time.</p>
<p>
<span class="versionmodified">New in version 2.3.</span></p>
</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.buffer_used">
<tt class="descclassname">xmlparser.</tt><tt class="descname">buffer_used</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.buffer_used" title="Permalink to this definition">¶</a></dt>
<dd><p>If <a title="xml.parsers.expat.xmlparser.buffer_text" class="reference internal" href="#xml.parsers.expat.xmlparser.buffer_text"><tt class="xref docutils literal"><span class="pre">buffer_text</span></tt></a> is enabled, the number of bytes stored in the buffer.
These bytes represent UTF-8 encoded text.  This attribute has no meaningful
interpretation when <a title="xml.parsers.expat.xmlparser.buffer_text" class="reference internal" href="#xml.parsers.expat.xmlparser.buffer_text"><tt class="xref docutils literal"><span class="pre">buffer_text</span></tt></a> is false.</p>
<p>
<span class="versionmodified">New in version 2.3.</span></p>
</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.ordered_attributes">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ordered_attributes</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.ordered_attributes" title="Permalink to this definition">¶</a></dt>
<dd><p>Setting this attribute to a non-zero integer causes the attributes to be
reported as a list rather than a dictionary.  The attributes are presented in
the order found in the document text.  For each attribute, two list entries are
presented: the attribute name and the attribute value.  (Older versions of this
module also used this format.)  By default, this attribute is false; it may be
changed at any time.</p>
<p>
<span class="versionmodified">New in version 2.1.</span></p>
</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.returns_unicode">
<tt class="descclassname">xmlparser.</tt><tt class="descname">returns_unicode</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.returns_unicode" title="Permalink to this definition">¶</a></dt>
<dd><p>If this attribute is set to a non-zero integer, the handler functions will be
passed Unicode strings.  If <a title="xml.parsers.expat.xmlparser.returns_unicode" class="reference internal" href="#xml.parsers.expat.xmlparser.returns_unicode"><tt class="xref docutils literal"><span class="pre">returns_unicode</span></tt></a> is <a title="False" class="reference external" href="constants.html#False"><tt class="xref xref docutils literal"><span class="pre">False</span></tt></a>, 8-bit
strings containing UTF-8 encoded data will be passed to the handlers.  This is
<a title="True" class="reference external" href="constants.html#True"><tt class="xref xref docutils literal"><span class="pre">True</span></tt></a> by default when Python is built with Unicode support.</p>
<p>
<span class="versionmodified">Changed in version 1.6: </span>Can be changed at any time to affect the result type.</p>
</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.specified_attributes">
<tt class="descclassname">xmlparser.</tt><tt class="descname">specified_attributes</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.specified_attributes" title="Permalink to this definition">¶</a></dt>
<dd><p>If set to a non-zero integer, the parser will report only those attributes which
were specified in the document instance and not those which were derived from
attribute declarations.  Applications which set this need to be especially
careful to use what additional information is available from the declarations as
needed to comply with the standards for the behavior of XML processors.  By
default, this attribute is false; it may be changed at any time.</p>
<p>
<span class="versionmodified">New in version 2.1.</span></p>
</dd></dl>

<p>The following attributes contain values relating to the most recent error
encountered by an <tt class="xref docutils literal"><span class="pre">xmlparser</span></tt> object, and will only have correct values
once a call to <tt class="xref docutils literal"><span class="pre">Parse()</span></tt> or <tt class="xref docutils literal"><span class="pre">ParseFile()</span></tt> has raised a
<a title="xml.parsers.expat.ExpatError" class="reference internal" href="#xml.parsers.expat.ExpatError"><tt class="xref docutils literal"><span class="pre">xml.parsers.expat.ExpatError</span></tt></a> exception.</p>
<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.ErrorByteIndex">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ErrorByteIndex</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.ErrorByteIndex" title="Permalink to this definition">¶</a></dt>
<dd>Byte index at which an error occurred.</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.ErrorCode">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ErrorCode</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.ErrorCode" title="Permalink to this definition">¶</a></dt>
<dd>Numeric code specifying the problem.  This value can be passed to the
<a title="xml.parsers.expat.ErrorString" class="reference internal" href="#xml.parsers.expat.ErrorString"><tt class="xref docutils literal"><span class="pre">ErrorString()</span></tt></a> function, or compared to one of the constants defined in the
<tt class="docutils literal"><span class="pre">errors</span></tt> object.</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.ErrorColumnNumber">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ErrorColumnNumber</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.ErrorColumnNumber" title="Permalink to this definition">¶</a></dt>
<dd>Column number at which an error occurred.</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.ErrorLineNumber">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ErrorLineNumber</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.ErrorLineNumber" title="Permalink to this definition">¶</a></dt>
<dd>Line number at which an error occurred.</dd></dl>

<p>The following attributes contain values relating to the current parse location
in an <tt class="xref docutils literal"><span class="pre">xmlparser</span></tt> object.  During a callback reporting a parse event they
indicate the location of the first of the sequence of characters that generated
the event.  When called outside of a callback, the position indicated will be
just past the last parse event (regardless of whether there was an associated
callback).</p>
<p>
<span class="versionmodified">New in version 2.4.</span></p>
<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.CurrentByteIndex">
<tt class="descclassname">xmlparser.</tt><tt class="descname">CurrentByteIndex</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.CurrentByteIndex" title="Permalink to this definition">¶</a></dt>
<dd>Current byte index in the parser input.</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.CurrentColumnNumber">
<tt class="descclassname">xmlparser.</tt><tt class="descname">CurrentColumnNumber</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.CurrentColumnNumber" title="Permalink to this definition">¶</a></dt>
<dd>Current column number in the parser input.</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.xmlparser.CurrentLineNumber">
<tt class="descclassname">xmlparser.</tt><tt class="descname">CurrentLineNumber</tt><a class="headerlink" href="#xml.parsers.expat.xmlparser.CurrentLineNumber" title="Permalink to this definition">¶</a></dt>
<dd>Current line number in the parser input.</dd></dl>

<p>Here is the list of handlers that can be set.  To set a handler on an
<tt class="xref docutils literal"><span class="pre">xmlparser</span></tt> object <em>o</em>, use <tt class="docutils literal"><span class="pre">o.handlername</span> <span class="pre">=</span> <span class="pre">func</span></tt>.  <em>handlername</em> must
be taken from the following list, and <em>func</em> must be a callable object accepting
the correct number of arguments.  The arguments are all strings, unless
otherwise stated.</p>
<dl class="method">
<dt id="xml.parsers.expat.xmlparser.XmlDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">XmlDeclHandler</tt><big>(</big><em>version</em>, <em>encoding</em>, <em>standalone</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.XmlDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd><p>Called when the XML declaration is parsed.  The XML declaration is the
(optional) declaration of the applicable version of the XML recommendation, the
encoding of the document text, and an optional &#8220;standalone&#8221; declaration.
<em>version</em> and <em>encoding</em> will be strings of the type dictated by the
<a title="xml.parsers.expat.xmlparser.returns_unicode" class="reference internal" href="#xml.parsers.expat.xmlparser.returns_unicode"><tt class="xref docutils literal"><span class="pre">returns_unicode</span></tt></a> attribute, and <em>standalone</em> will be <tt class="docutils literal"><span class="pre">1</span></tt> if the
document is declared standalone, <tt class="docutils literal"><span class="pre">0</span></tt> if it is declared not to be standalone,
or <tt class="docutils literal"><span class="pre">-1</span></tt> if the standalone clause was omitted. This is only available with
Expat version 1.95.0 or newer.</p>
<p>
<span class="versionmodified">New in version 2.1.</span></p>
</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.StartDoctypeDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">StartDoctypeDeclHandler</tt><big>(</big><em>doctypeName</em>, <em>systemId</em>, <em>publicId</em>, <em>has_internal_subset</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.StartDoctypeDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called when Expat begins parsing the document type declaration (<tt class="docutils literal"><span class="pre">&lt;!DOCTYPE</span>
<span class="pre">...</span></tt>).  The <em>doctypeName</em> is provided exactly as presented.  The <em>systemId</em> and
<em>publicId</em> parameters give the system and public identifiers if specified, or
<tt class="xref docutils literal"><span class="pre">None</span></tt> if omitted.  <em>has_internal_subset</em> will be true if the document
contains and internal document declaration subset. This requires Expat version
1.2 or newer.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.EndDoctypeDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">EndDoctypeDeclHandler</tt><big>(</big><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.EndDoctypeDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called when Expat is done parsing the document type declaration. This requires
Expat version 1.2 or newer.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.ElementDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ElementDeclHandler</tt><big>(</big><em>name</em>, <em>model</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.ElementDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called once for each element type declaration.  <em>name</em> is the name of the
element type, and <em>model</em> is a representation of the content model.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.AttlistDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">AttlistDeclHandler</tt><big>(</big><em>elname</em>, <em>attname</em>, <em>type</em>, <em>default</em>, <em>required</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.AttlistDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called for each declared attribute for an element type.  If an attribute list
declaration declares three attributes, this handler is called three times, once
for each attribute.  <em>elname</em> is the name of the element to which the
declaration applies and <em>attname</em> is the name of the attribute declared.  The
attribute type is a string passed as <em>type</em>; the possible values are
<tt class="docutils literal"><span class="pre">'CDATA'</span></tt>, <tt class="docutils literal"><span class="pre">'ID'</span></tt>, <tt class="docutils literal"><span class="pre">'IDREF'</span></tt>, ... <em>default</em> gives the default value for
the attribute used when the attribute is not specified by the document instance,
or <tt class="xref docutils literal"><span class="pre">None</span></tt> if there is no default value (<tt class="docutils literal"><span class="pre">#IMPLIED</span></tt> values).  If the
attribute is required to be given in the document instance, <em>required</em> will be
true. This requires Expat version 1.95.0 or newer.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.StartElementHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">StartElementHandler</tt><big>(</big><em>name</em>, <em>attributes</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.StartElementHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called for the start of every element.  <em>name</em> is a string containing the
element name, and <em>attributes</em> is a dictionary mapping attribute names to their
values.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.EndElementHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">EndElementHandler</tt><big>(</big><em>name</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.EndElementHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called for the end of every element.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.ProcessingInstructionHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ProcessingInstructionHandler</tt><big>(</big><em>target</em>, <em>data</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.ProcessingInstructionHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called for every processing instruction.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.CharacterDataHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">CharacterDataHandler</tt><big>(</big><em>data</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.CharacterDataHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called for character data.  This will be called for normal character data, CDATA
marked content, and ignorable whitespace.  Applications which must distinguish
these cases can use the <a title="xml.parsers.expat.xmlparser.StartCdataSectionHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.StartCdataSectionHandler"><tt class="xref docutils literal"><span class="pre">StartCdataSectionHandler</span></tt></a>,
<a title="xml.parsers.expat.xmlparser.EndCdataSectionHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.EndCdataSectionHandler"><tt class="xref docutils literal"><span class="pre">EndCdataSectionHandler</span></tt></a>, and <a title="xml.parsers.expat.xmlparser.ElementDeclHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.ElementDeclHandler"><tt class="xref docutils literal"><span class="pre">ElementDeclHandler</span></tt></a> callbacks to
collect the required information.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.UnparsedEntityDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">UnparsedEntityDeclHandler</tt><big>(</big><em>entityName</em>, <em>base</em>, <em>systemId</em>, <em>publicId</em>, <em>notationName</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.UnparsedEntityDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called for unparsed (NDATA) entity declarations.  This is only present for
version 1.2 of the Expat library; for more recent versions, use
<a title="xml.parsers.expat.xmlparser.EntityDeclHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.EntityDeclHandler"><tt class="xref docutils literal"><span class="pre">EntityDeclHandler</span></tt></a> instead.  (The underlying function in the Expat
library has been declared obsolete.)</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.EntityDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">EntityDeclHandler</tt><big>(</big><em>entityName</em>, <em>is_parameter_entity</em>, <em>value</em>, <em>base</em>, <em>systemId</em>, <em>publicId</em>, <em>notationName</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.EntityDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd><p>Called for all entity declarations.  For parameter and internal entities,
<em>value</em> will be a string giving the declared contents of the entity; this will
be <tt class="xref docutils literal"><span class="pre">None</span></tt> for external entities.  The <em>notationName</em> parameter will be
<tt class="xref docutils literal"><span class="pre">None</span></tt> for parsed entities, and the name of the notation for unparsed
entities. <em>is_parameter_entity</em> will be true if the entity is a parameter entity
or false for general entities (most applications only need to be concerned with
general entities). This is only available starting with version 1.95.0 of the
Expat library.</p>
<p>
<span class="versionmodified">New in version 2.1.</span></p>
</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.NotationDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">NotationDeclHandler</tt><big>(</big><em>notationName</em>, <em>base</em>, <em>systemId</em>, <em>publicId</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.NotationDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called for notation declarations.  <em>notationName</em>, <em>base</em>, and <em>systemId</em>, and
<em>publicId</em> are strings if given.  If the public identifier is omitted,
<em>publicId</em> will be <tt class="xref docutils literal"><span class="pre">None</span></tt>.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.StartNamespaceDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">StartNamespaceDeclHandler</tt><big>(</big><em>prefix</em>, <em>uri</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.StartNamespaceDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called when an element contains a namespace declaration.  Namespace declarations
are processed before the <a title="xml.parsers.expat.xmlparser.StartElementHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.StartElementHandler"><tt class="xref docutils literal"><span class="pre">StartElementHandler</span></tt></a> is called for the element
on which declarations are placed.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.EndNamespaceDeclHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">EndNamespaceDeclHandler</tt><big>(</big><em>prefix</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.EndNamespaceDeclHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called when the closing tag is reached for an element  that contained a
namespace declaration.  This is called once for each namespace declaration on
the element in the reverse of the order for which the
<a title="xml.parsers.expat.xmlparser.StartNamespaceDeclHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.StartNamespaceDeclHandler"><tt class="xref docutils literal"><span class="pre">StartNamespaceDeclHandler</span></tt></a> was called to indicate the start of each
namespace declaration&#8217;s scope.  Calls to this handler are made after the
corresponding <a title="xml.parsers.expat.xmlparser.EndElementHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.EndElementHandler"><tt class="xref docutils literal"><span class="pre">EndElementHandler</span></tt></a> for the end of the element.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.CommentHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">CommentHandler</tt><big>(</big><em>data</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.CommentHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called for comments.  <em>data</em> is the text of the comment, excluding the leading
&#8216;<tt class="docutils literal"><span class="pre">&lt;!-</span></tt><tt class="docutils literal"><span class="pre">-</span></tt>&#8216; and trailing &#8216;<tt class="docutils literal"><span class="pre">-</span></tt><tt class="docutils literal"><span class="pre">-&gt;</span></tt>&#8216;.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.StartCdataSectionHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">StartCdataSectionHandler</tt><big>(</big><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.StartCdataSectionHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called at the start of a CDATA section.  This and <a title="xml.parsers.expat.xmlparser.EndCdataSectionHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.EndCdataSectionHandler"><tt class="xref docutils literal"><span class="pre">EndCdataSectionHandler</span></tt></a>
are needed to be able to identify the syntactical start and end for CDATA
sections.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.EndCdataSectionHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">EndCdataSectionHandler</tt><big>(</big><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.EndCdataSectionHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called at the end of a CDATA section.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.DefaultHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">DefaultHandler</tt><big>(</big><em>data</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.DefaultHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called for any characters in the XML document for which no applicable handler
has been specified.  This means characters that are part of a construct which
could be reported, but for which no handler has been supplied.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.DefaultHandlerExpand">
<tt class="descclassname">xmlparser.</tt><tt class="descname">DefaultHandlerExpand</tt><big>(</big><em>data</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.DefaultHandlerExpand" title="Permalink to this definition">¶</a></dt>
<dd>This is the same as the <a title="xml.parsers.expat.xmlparser.DefaultHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.DefaultHandler"><tt class="xref docutils literal"><span class="pre">DefaultHandler()</span></tt></a>,  but doesn&#8217;t inhibit expansion
of internal entities. The entity reference will not be passed to the default
handler.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.NotStandaloneHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">NotStandaloneHandler</tt><big>(</big><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.NotStandaloneHandler" title="Permalink to this definition">¶</a></dt>
<dd>Called if the XML document hasn&#8217;t been declared as being a standalone document.
This happens when there is an external subset or a reference to a parameter
entity, but the XML declaration does not set standalone to <tt class="docutils literal"><span class="pre">yes</span></tt> in an XML
declaration.  If this handler returns <tt class="docutils literal"><span class="pre">0</span></tt>, then the parser will throw an
<tt class="xref docutils literal"><span class="pre">XML_ERROR_NOT_STANDALONE</span></tt> error.  If this handler is not set, no
exception is raised by the parser for this condition.</dd></dl>

<dl class="method">
<dt id="xml.parsers.expat.xmlparser.ExternalEntityRefHandler">
<tt class="descclassname">xmlparser.</tt><tt class="descname">ExternalEntityRefHandler</tt><big>(</big><em>context</em>, <em>base</em>, <em>systemId</em>, <em>publicId</em><big>)</big><a class="headerlink" href="#xml.parsers.expat.xmlparser.ExternalEntityRefHandler" title="Permalink to this definition">¶</a></dt>
<dd><p>Called for references to external entities.  <em>base</em> is the current base, as set
by a previous call to <a title="xml.parsers.expat.xmlparser.SetBase" class="reference internal" href="#xml.parsers.expat.xmlparser.SetBase"><tt class="xref docutils literal"><span class="pre">SetBase()</span></tt></a>.  The public and system identifiers,
<em>systemId</em> and <em>publicId</em>, are strings if given; if the public identifier is not
given, <em>publicId</em> will be <tt class="xref docutils literal"><span class="pre">None</span></tt>.  The <em>context</em> value is opaque and should
only be used as described below.</p>
<p>For external entities to be parsed, this handler must be implemented. It is
responsible for creating the sub-parser using
<tt class="docutils literal"><span class="pre">ExternalEntityParserCreate(context)</span></tt>, initializing it with the appropriate
callbacks, and parsing the entity.  This handler should return an integer; if it
returns <tt class="docutils literal"><span class="pre">0</span></tt>, the parser will throw an
<tt class="xref docutils literal"><span class="pre">XML_ERROR_EXTERNAL_ENTITY_HANDLING</span></tt> error, otherwise parsing will
continue.</p>
<p>If this handler is not provided, external entities are reported by the
<a title="xml.parsers.expat.xmlparser.DefaultHandler" class="reference internal" href="#xml.parsers.expat.xmlparser.DefaultHandler"><tt class="xref docutils literal"><span class="pre">DefaultHandler</span></tt></a> callback, if provided.</p>
</dd></dl>

</div>
<div class="section" id="expaterror-exceptions">
<span id="expaterror-objects"></span><h2>20.5.2. ExpatError Exceptions<a class="headerlink" href="#expaterror-exceptions" title="Permalink to this headline">¶</a></h2>
<p><a title="xml.parsers.expat.ExpatError" class="reference internal" href="#xml.parsers.expat.ExpatError"><tt class="xref docutils literal"><span class="pre">ExpatError</span></tt></a> exceptions have a number of interesting attributes:</p>
<dl class="attribute">
<dt id="xml.parsers.expat.ExpatError.code">
<tt class="descclassname">ExpatError.</tt><tt class="descname">code</tt><a class="headerlink" href="#xml.parsers.expat.ExpatError.code" title="Permalink to this definition">¶</a></dt>
<dd><p>Expat&#8217;s internal error number for the specific error.  This will match one of
the constants defined in the <tt class="docutils literal"><span class="pre">errors</span></tt> object from this module.</p>
<p>
<span class="versionmodified">New in version 2.1.</span></p>
</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.ExpatError.lineno">
<tt class="descclassname">ExpatError.</tt><tt class="descname">lineno</tt><a class="headerlink" href="#xml.parsers.expat.ExpatError.lineno" title="Permalink to this definition">¶</a></dt>
<dd><p>Line number on which the error was detected.  The first line is numbered <tt class="docutils literal"><span class="pre">1</span></tt>.</p>
<p>
<span class="versionmodified">New in version 2.1.</span></p>
</dd></dl>

<dl class="attribute">
<dt id="xml.parsers.expat.ExpatError.offset">
<tt class="descclassname">ExpatError.</tt><tt class="descname">offset</tt><a class="headerlink" href="#xml.parsers.expat.ExpatError.offset" title="Permalink to this definition">¶</a></dt>
<dd><p>Character offset into the line where the error occurred.  The first column is
numbered <tt class="docutils literal"><span class="pre">0</span></tt>.</p>
<p>
<span class="versionmodified">New in version 2.1.</span></p>
</dd></dl>

</div>
<div class="section" id="example">
<span id="expat-example"></span><h2>20.5.3. Example<a class="headerlink" href="#example" title="Permalink to this headline">¶</a></h2>
<p>The following program defines three handlers that just print out their
arguments.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">xml.parsers.expat</span>

<span class="c"># 3 handler functions</span>
<span class="k">def</span> <span class="nf">start_element</span><span class="p">(</span><span class="n">name</span><span class="p">,</span> <span class="n">attrs</span><span class="p">):</span>
    <span class="k">print</span> <span class="s">&#39;Start element:&#39;</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="n">attrs</span>
<span class="k">def</span> <span class="nf">end_element</span><span class="p">(</span><span class="n">name</span><span class="p">):</span>
    <span class="k">print</span> <span class="s">&#39;End element:&#39;</span><span class="p">,</span> <span class="n">name</span>
<span class="k">def</span> <span class="nf">char_data</span><span class="p">(</span><span class="n">data</span><span class="p">):</span>
    <span class="k">print</span> <span class="s">&#39;Character data:&#39;</span><span class="p">,</span> <span class="nb">repr</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>

<span class="n">p</span> <span class="o">=</span> <span class="n">xml</span><span class="o">.</span><span class="n">parsers</span><span class="o">.</span><span class="n">expat</span><span class="o">.</span><span class="n">ParserCreate</span><span class="p">()</span>

<span class="n">p</span><span class="o">.</span><span class="n">StartElementHandler</span> <span class="o">=</span> <span class="n">start_element</span>
<span class="n">p</span><span class="o">.</span><span class="n">EndElementHandler</span> <span class="o">=</span> <span class="n">end_element</span>
<span class="n">p</span><span class="o">.</span><span class="n">CharacterDataHandler</span> <span class="o">=</span> <span class="n">char_data</span>

<span class="n">p</span><span class="o">.</span><span class="n">Parse</span><span class="p">(</span><span class="s">&quot;&quot;&quot;&lt;?xml version=&quot;1.0&quot;?&gt;</span>
<span class="s">&lt;parent id=&quot;top&quot;&gt;&lt;child1 name=&quot;paul&quot;&gt;Text goes here&lt;/child1&gt;</span>
<span class="s">&lt;child2 name=&quot;fred&quot;&gt;More text&lt;/child2&gt;</span>
<span class="s">&lt;/parent&gt;&quot;&quot;&quot;</span><span class="p">,</span> <span class="mf">1</span><span class="p">)</span>
</pre></div>
</div>
<p>The output from this program is:</p>
<div class="highlight-python"><pre>Start element: parent {'id': 'top'}
Start element: child1 {'name': 'paul'}
Character data: 'Text goes here'
End element: child1
Character data: '\n'
Start element: child2 {'name': 'fred'}
Character data: 'More text'
End element: child2
Character data: '\n'
End element: parent</pre>
</div>
</div>
<div class="section" id="content-model-descriptions">
<span id="expat-content-models"></span><h2>20.5.4. Content Model Descriptions<a class="headerlink" href="#content-model-descriptions" title="Permalink to this headline">¶</a></h2>
<p>Content modules are described using nested tuples.  Each tuple contains four
values: the type, the quantifier, the name, and a tuple of children.  Children
are simply additional content module descriptions.</p>
<p>The values of the first two fields are constants defined in the <tt class="docutils literal"><span class="pre">model</span></tt> object
of the <tt class="xref docutils literal"><span class="pre">xml.parsers.expat</span></tt> module.  These constants can be collected in two
groups: the model type group and the quantifier group.</p>
<p>The constants in the model type group are:</p>
<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CTYPE_ANY</tt></dt>
<dd>The element named by the model name was declared to have a content model of
<tt class="docutils literal"><span class="pre">ANY</span></tt>.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CTYPE_CHOICE</tt></dt>
<dd>The named element allows a choice from a number of options; this is used for
content models such as <tt class="docutils literal"><span class="pre">(A</span> <span class="pre">|</span> <span class="pre">B</span> <span class="pre">|</span> <span class="pre">C)</span></tt>.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CTYPE_EMPTY</tt></dt>
<dd>Elements which are declared to be <tt class="docutils literal"><span class="pre">EMPTY</span></tt> have this model type.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CTYPE_MIXED</tt></dt>
<dd></dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CTYPE_NAME</tt></dt>
<dd></dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CTYPE_SEQ</tt></dt>
<dd>Models which represent a series of models which follow one after the other are
indicated with this model type.  This is used for models such as <tt class="docutils literal"><span class="pre">(A,</span> <span class="pre">B,</span> <span class="pre">C)</span></tt>.</dd></dl>

<p>The constants in the quantifier group are:</p>
<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CQUANT_NONE</tt></dt>
<dd>No modifier is given, so it can appear exactly once, as for <tt class="docutils literal"><span class="pre">A</span></tt>.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CQUANT_OPT</tt></dt>
<dd>The model is optional: it can appear once or not at all, as for <tt class="docutils literal"><span class="pre">A?</span></tt>.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CQUANT_PLUS</tt></dt>
<dd>The model must occur one or more times (like <tt class="docutils literal"><span class="pre">A+</span></tt>).</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_CQUANT_REP</tt></dt>
<dd>The model must occur zero or more times, as for <tt class="docutils literal"><span class="pre">A*</span></tt>.</dd></dl>

</div>
<div class="section" id="expat-error-constants">
<span id="expat-errors"></span><h2>20.5.5. Expat error constants<a class="headerlink" href="#expat-error-constants" title="Permalink to this headline">¶</a></h2>
<p>The following constants are provided in the <tt class="docutils literal"><span class="pre">errors</span></tt> object of the
<tt class="xref docutils literal"><span class="pre">xml.parsers.expat</span></tt> module.  These constants are useful in interpreting
some of the attributes of the <a title="xml.parsers.expat.ExpatError" class="reference internal" href="#xml.parsers.expat.ExpatError"><tt class="xref docutils literal"><span class="pre">ExpatError</span></tt></a> exception objects raised when an
error has occurred.</p>
<p>The <tt class="docutils literal"><span class="pre">errors</span></tt> object has the following attributes:</p>
<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_ASYNC_ENTITY</tt></dt>
<dd></dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF</tt></dt>
<dd>An entity reference in an attribute value referred to an external entity instead
of an internal entity.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_BAD_CHAR_REF</tt></dt>
<dd>A character reference referred to a character which is illegal in XML (for
example, character <tt class="docutils literal"><span class="pre">0</span></tt>, or &#8216;<tt class="docutils literal"><span class="pre">&amp;#0;</span></tt>&#8216;).</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_BINARY_ENTITY_REF</tt></dt>
<dd>An entity reference referred to an entity which was declared with a notation, so
cannot be parsed.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_DUPLICATE_ATTRIBUTE</tt></dt>
<dd>An attribute was used more than once in a start tag.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_INCORRECT_ENCODING</tt></dt>
<dd></dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_INVALID_TOKEN</tt></dt>
<dd>Raised when an input byte could not properly be assigned to a character; for
example, a NUL byte (value <tt class="docutils literal"><span class="pre">0</span></tt>) in a UTF-8 input stream.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_JUNK_AFTER_DOC_ELEMENT</tt></dt>
<dd>Something other than whitespace occurred after the document element.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_MISPLACED_XML_PI</tt></dt>
<dd>An XML declaration was found somewhere other than the start of the input data.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_NO_ELEMENTS</tt></dt>
<dd>The document contains no elements (XML requires all documents to contain exactly
one top-level element)..</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_NO_MEMORY</tt></dt>
<dd>Expat was not able to allocate memory internally.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_PARAM_ENTITY_REF</tt></dt>
<dd>A parameter entity reference was found where it was not allowed.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_PARTIAL_CHAR</tt></dt>
<dd>An incomplete character was found in the input.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_RECURSIVE_ENTITY_REF</tt></dt>
<dd>An entity reference contained another reference to the same entity; possibly via
a different name, and possibly indirectly.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_SYNTAX</tt></dt>
<dd>Some unspecified syntax error was encountered.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_TAG_MISMATCH</tt></dt>
<dd>An end tag did not match the innermost open start tag.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_UNCLOSED_TOKEN</tt></dt>
<dd>Some token (such as a start tag) was not closed before the end of the stream or
the next token was encountered.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_UNDEFINED_ENTITY</tt></dt>
<dd>A reference was made to a entity which was not defined.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_UNKNOWN_ENCODING</tt></dt>
<dd>The document encoding is not supported by Expat.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_UNCLOSED_CDATA_SECTION</tt></dt>
<dd>A CDATA marked section was not closed.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_EXTERNAL_ENTITY_HANDLING</tt></dt>
<dd></dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_NOT_STANDALONE</tt></dt>
<dd>The parser determined that the document was not &#8220;standalone&#8221; though it declared
itself to be in the XML declaration, and the <tt class="xref docutils literal"><span class="pre">NotStandaloneHandler</span></tt> was
set and returned <tt class="docutils literal"><span class="pre">0</span></tt>.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_UNEXPECTED_STATE</tt></dt>
<dd></dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_ENTITY_DECLARED_IN_PE</tt></dt>
<dd></dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_FEATURE_REQUIRES_XML_DTD</tt></dt>
<dd>An operation was requested that requires DTD support to be compiled in, but
Expat was configured without DTD support.  This should never be reported by a
standard build of the <tt class="xref docutils literal"><span class="pre">xml.parsers.expat</span></tt> module.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING</tt></dt>
<dd>A behavioral change was requested after parsing started that can only be changed
before parsing has started.  This is (currently) only raised by
<tt class="xref docutils literal"><span class="pre">UseForeignDTD()</span></tt>.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_UNBOUND_PREFIX</tt></dt>
<dd>An undeclared prefix was found when namespace processing was enabled.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_UNDECLARING_PREFIX</tt></dt>
<dd>The document attempted to remove the namespace declaration associated with a
prefix.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_INCOMPLETE_PE</tt></dt>
<dd>A parameter entity contained incomplete markup.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_XML_DECL</tt></dt>
<dd>The document contained no document element at all.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_TEXT_DECL</tt></dt>
<dd>There was an error parsing a text declaration in an external entity.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_PUBLICID</tt></dt>
<dd>Characters were found in the public id that are not allowed.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_SUSPENDED</tt></dt>
<dd>The requested operation was made on a suspended parser, but isn&#8217;t allowed.  This
includes attempts to provide additional input or to stop the parser.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_NOT_SUSPENDED</tt></dt>
<dd>An attempt to resume the parser was made when the parser had not been suspended.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_ABORTED</tt></dt>
<dd>This should not be reported to Python applications.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_FINISHED</tt></dt>
<dd>The requested operation was made on a parser which was finished parsing input,
but isn&#8217;t allowed.  This includes attempts to provide additional input or to
stop the parser.</dd></dl>

<dl class="data">
<dt>
<tt class="descclassname">xml.parsers.expat.</tt><tt class="descname">XML_ERROR_SUSPEND_PE</tt></dt>
<dd></dd></dl>

<p class="rubric">Footnotes</p>
<table class="docutils footnote" frame="void" id="id3" rules="none">
<colgroup><col class="label" /><col /></colgroup>
<tbody valign="top">
<tr><td class="label">[1]</td><td>The encoding string included in XML output should conform to the
appropriate standards. For example, &#8220;UTF-8&#8221; is valid, but &#8220;UTF8&#8221; is
not. See <a class="reference external" href="http://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl">http://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl</a>
and <a class="reference external" href="http://www.iana.org/assignments/character-sets">http://www.iana.org/assignments/character-sets</a> .</td></tr>
</tbody>
</table>
</div>
</div>


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            <ul>
<li><a class="reference external" href="">20.5. <tt class="docutils literal"><span class="pre">xml.parsers.expat</span></tt> &#8212; Fast XML parsing using Expat</a><ul>
<li><a class="reference external" href="#xmlparser-objects">20.5.1. XMLParser Objects</a></li>
<li><a class="reference external" href="#expaterror-exceptions">20.5.2. ExpatError Exceptions</a></li>
<li><a class="reference external" href="#example">20.5.3. Example</a></li>
<li><a class="reference external" href="#content-model-descriptions">20.5.4. Content Model Descriptions</a></li>
<li><a class="reference external" href="#expat-error-constants">20.5.5. Expat error constants</a></li>
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